Question about 1974 Yamaha DT 360
I was riding my 81 Yamaha 175 enduro last night down the street when i stopped to turn around and go home i noticed it was smoking really bad. Its still smoking pretty badly but is running fairly smooth. It has never done that before could i have ruined the rings that quick ? Also the oil light comes off and on there is plenty of 2 stroke oil in the oil tank
Same happended to me with exactly the same motorcycle... I solved the provblem by replacing the crankshaft oil seal on the rightside of the crankcase. It solved the problem immediatly!
Posted on Aug 08, 2009
Bad rings in a two stroke engine will not make the engine smoke more. It will do that in a four stroke but not a two stroke. The connecting rod in a 4 stroke is designed to splash oil onto the cylinder walls. The gearbox oil is also the engine oil. Bad rings will not wipe the cylinder walls clean so the oil left behind gets burned creating smoke. In a two stroke engine the gearbox oil does not come in contact with the crankshaft, connecting rod, or the cylinder. The two stroke oil is mixed into the gas and gets sucked from the carb into a sealed crankcase cavity, then goes into the cylinder then gets compressed and ignited then goes out the exhaust pipe. While in the crankcase, it is able to lube the cylinder walls, the crank bearings and the connecting rod bearings. The engine can not burn any more oil than the amount mixed into the gas, good rings or bad. Bad rings in a two stroke will only reduce performance.
Have you changed brands of 2 stroke oil? Using a synthetic oil? You are using 2 stroke engine oil in the oil tank and not motor oil > RIGHT? Never substitute motor oil for 2 stroke engine oil. Your oil pump is 28 years old, (unless it has been replaced at some time), and may be going bad. If I recall correctly, (Big IF ), the stroke on the pump is adjustable. Three different thicknesses of shims were available. The thicker the shim the less oil pumped. There is a nut, a spring washer, a large adjusting plate and then the smaller shim washer. I think the adj. plate was threaded. 28 years back makes it a bit hard to recall the details. Isn't the oil cable adjustable at the casing?
Hey, worst case you could plug the oil line and run a couple of tanks of gas mixed 32 to 1, gas and oil. Now you KNOW for sure how much oil is in the gas. 32 / 1 equals 4 ounces of oil per gallon of gas. The oil sensor switch could be bad or a loose or abraided wire may be present.
Please rate this solution. Thanks.
Posted on Jun 05, 2009
A 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
The service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Posted on Jan 02, 2017
Tips for a great answer:
Apr 23, 2015 | Yamaha Motorcycles
Nov 19, 2013 | Yamaha Motorcycles
Feb 18, 2012 | Yamaha DT 125 X Motorcycles
Jun 21, 2011 | Yamaha WR 125X Motorcycles
Feb 21, 2011 | 2004 Yamaha YZ 450 F
Feb 12, 2011 | 1972 Yamaha DT 360
Apr 16, 2010 | Yamaha Motorcycles
Sep 08, 2009 | 1972 Yamaha DT 360
Aug 02, 2009 | 1974 Yamaha DT 360
891 people viewed this question
Usually answered in minutes!
Step 2: Please assign your manual to a product: